spl: Kconfig: Replace CONFIG_SPL_FAT_SUPPORT with CONFIG_SPL_FS_FAT

Replace CONFIG_SPL_FAT_SUPPORT with CONFIG_SPL_FS_FAT so
obj-$(CONFIG_$(SPL_)FS_FAT) can be used to control the build in both
SPL and U-Boot.

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/sama5d27_som1_ek_mmc_defconfig b/configs/sama5d27_som1_ek_mmc_defconfig
index e260554..5dcd80c 100644
--- a/configs/sama5d27_som1_ek_mmc_defconfig
+++ b/configs/sama5d27_som1_ek_mmc_defconfig
@@ -13,7 +13,7 @@
 CONFIG_DEBUG_UART_BOARD_INIT=y
 CONFIG_DEBUG_UART_BASE=0xf8020000
 CONFIG_DEBUG_UART_CLOCK=82000000
-CONFIG_SPL_FAT_SUPPORT=y
+CONFIG_SPL_FS_FAT=y
 CONFIG_SPL_LIBDISK_SUPPORT=y
 CONFIG_DEBUG_UART=y
 CONFIG_ENV_VARS_UBOOT_CONFIG=y